<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="css.css" />
    <style>
        .container {
            display: flex;
            flex-direction: column;
            width: 50vw;
            margin: 0 auto;
            background: rgb(197, 193, 193);
            height: 200vh;
            padding: 20px;
            flex-wrap: wrap;
        }

        h5 {
            width: 100px;
        }

        .aa {
            width: 100px;
            height: 100px;
            margin: 10px;
        }

        .a1 {

            border: 10px solid hsla(0, 0%, 100%, 0.5);
            background-color: #000;
            /* background-clip: padding-box; */
        }

        .a2 {

            background: green;
            box-shadow: 0 0 0 10px #655,
                0 0 0 15px yellow,
                0 2px 5px 25px blue;
        }

        .a3 {
            background: linear-gradient(#fb3 50%, #58a 50%);
            background-size: 100% 20px;
        }

        .a4 {
            background: linear-gradient(#fb3 33%, #58a 66%, pink 1%);
            background-size: 100% 20px;
        }

        .a5 {
            background: linear-gradient(to right, #fb3 50%, rgb(0, 0, 0, 0.5) 0);
            background-size: 30px 100%
        }

        .a6 {
            background: linear-gradient(45deg, #fb3 50%, #58a 0);
            background-size: 30px 30px;
        }

        .a7 {
            background: linear-gradient(45deg, #fb3 25%, #58a 0, #58a 50%, #fb3 0, #fb3 75%, #58a 0);
            background-size: 30px 30px;
        }
    </style>
</head>

<body>
    <div class="container">
        <h5>半透明边框</h5>
        <div class="a1 aa"></div>
        <h5>多重边框</h5>
        <div class="a2 aa"></div>
        <h5>条纹背景</h5>
        <div class="a3 aa"></div>
        <div class="a4 aa"></div>
        <div class="a5 aa"></div>
        <div class="a6 aa"></div>
        <div class="a7 aa"></div>
        <h5>网格</h5>
        <div class="a8 aa"></div>
        <div class="a9 aa"></div>
        <div class="a10 aa"></div>
        <h5>波点</h5>
        <div class="aa a11"></div>
        <div class="aa a12"></div>
        <h5>信封边框</h5>
        <div class="aa a13"></div>
        <div class="aa a14"></div>
        <h5>蚂蚁行军边框</h5>
        <div class="aa a15"></div>

    </div>
</body>

</html>